Use backward-compatibility-only mock fixture to ensure complete coverage

Author: nicoddemus

test_pytest_mock.py

@@ -111,3 +111,13 @@ def test_foo(mock, tmpdir):
     ''')
     result = testdir.runpytest('-s')
     result.stderr.fnmatch_lines(['*"mock" fixture has been deprecated*'])
+
+
+def test_deprecated_mock(mock, tmpdir):
+    """
+    Use backward-compatibility-only mock fixture to ensure complete coverage.
+    """
+    mock.patch('os.listdir', return_value=['mocked'])
+    assert os.listdir(str(tmpdir)) == ['mocked']
+    mock.stopall()
+    assert os.listdir(str(tmpdir)) == []